03 yz45f

hey folks am new too the site bought a 03 yz450f mx bike ....was just wondering about rebuilds how often they need them .....everything seems ok starts first kick plenty of power not burning oil,have been on road bikes all my life so am new too this any advice ...........:smirk:

hey folks am new too the site bought a 03 yz450f mx bike ....was just wondering about rebuilds how often they need them .....everything seems ok starts first kick plenty of power not burning oil,have been on road bikes all my life so am new too this any advice ...........:smirk:

Top end life is usually 200+ hours on a trail ridden machine. Racing will shorten top end life somewhat.

If it runs fine just ride and enjoy it. Do oil/filter changes every 20-30 hours (about 500 miles) if it's not a race machine.

Read through the Common Threads sticky, as a lot of things that come up all the time are in there. There's a link to service manuals down page two.

I think if there was one serious flaw in the '03, it was the rod bearing. The crank was revised in '04 and again in '05 to beef the bearing up, and all OEM cranks sold for the '03 since that time are all the revised version. It's not really that failures were ever really common, it's just that when a big end seizes, the amount of damage can potentially be staggering, so it gets noticed even when a relatively few people destroy entire engines. I owned an '03 that I know was running fine with 350-400 hours on it. I've heard of them going much farther, too, but there's that one that breaks, you know?

If you feel inspired to, you might decide to put a fresh set of rings in it just as an excuse to inspect the crank, or you can just run it. It's a risk, but the odds in your favor are pretty good.

thanks for quick reply guys as i said im new too all this ,its not for racing just my own personal use for a bit of crack and im lovin it ,its the grin factor all the way ....

I bought one new when they came out. It got raced every weekend for 3 years. I still have it and it gets rode frequently. I like the 4 speed and the motor runs as hard as anything out there. It probably has upwards of 500 hours and has never had anything done but alot of maintenance. All the yam 4 strokes i ve owned have been bullet proof.

I agree with liking the 4 speed trans (especially when duning). Glad to hear that it has been a strong running and reliable bike. I have enjoyed mine tremendously:thumbsup:

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